Recovery of phenols from mineral oils



Aug 24, 1943- M. c. K. JONES E1-AL 2,327,526 y RECOVERY OF PHENOLS FROM MINERAL 011.18 l I Filed June 22, 1940 2 Sheets-Sheet l Hg .504 (4 Tree/ed 0/7 mm 8 f 1%; 2Q /9A fzf img/fg Ffa-1 f Aug. 24, 1943. A M. c. K. JONES ET AL RECOVERY OF PHENOLS FROM MINERAL OILS Filed June 22, 1940 2 she'etsfshreet 2 76]???{72 l j y N '64 Patentes Aug. l24, 1943 2,327,526 RECOVERY F Pllllls FROM EBAL Minor C.. K. Jones, Elizabeth,

Strickland, ltoselle, N. J., assignors and Barney E. to Standard Oil Development Company, a corporation of Delaware Application .nine 22,1940, serial No. 341,818

(ci. 26o-ser) 3 Claims.

The present invention relates to the rening of mineral oils. The invention is especially concerned with the removal, segregation and recovery of naturally occurring acidic oxygen containing compounds froin mineral oils containing the same. 'Ihe invention is particularly concerned with an improved method for the removal l and recovery of petroleum oil phenols and petroleum oil naphthenic acids utilizing a solid reagent selected from the class of alkali metal aluminum silicates of the zeolite type. jIhe present invention not only recovers these valuable materials in aneiiicient and economical manner, bug also Produces a high quality treated oil produc It is known in the art to remove and recover petroleum oil phenols, as Well as petroleum oil naphthenic acids byl various methods since these materials are relatively valuable and are desirable, for example, as inhibiting agents and as intermediate feed products. One method currently employed is to contact the phenol and naphthenic acid containing petroleum oil with various aqueous solutions of alkali metal hydroxides and the like in order to form the corresponding phenolates and naphthenates. Thesesalts are soluble in and are removed with the spent aqueous alkali metal hydroxide solution. The corresponding phenols are then recovered from the salts by treating the same with dilute acids and the like in order to form the corresponding phenols or naphthenic acids.

We have now discovered an improved method 'of removing and recovering these valuable constituents from feed oils containing the same in an. eillcient manner by which a. high yield is secured and which also results in the production of a treated oil product of high quality. In accordance with our invention the mineral oil containing the recoverable phenolic type compounds and naphthenic acids is contacted with a solid reagent, selected from the class of alkali metal aluminum silicates of the zeolite type, under conditions to substantially, fully remove these constituents from the feed oil. The spent solid reagent is then handled in a manner to remove, segregate, and recover the phenolic type Acompounds and naphthenlc acids from the reagent and to fully regenerate or revivlfy the same. The process of our invention may be readily low boiling petroleum oil understood by reference to the attached drawings illustrating modifications of the same.

Figure 1 illustrates a modification vofthe 1nvention in which the feed oil is passed through a bed of the solid reagent. while Figure 2 illustrates another modification in which a` slurry of I the solid reagent is utilized. Referring particularly to Figure l, it is assumed that the phenolic type constituent and naphthenic acid containing feed oil is a petroleum oil boiling in the kerosene oil boiling range. For purposes of illustration it is also assumed that the solid reagent is a naturally occurring hydrated aluminum silicate of the zeolite type and that two zeolite contacting units are employed. It is to be understood that any number of units may be utilized and may be arranged in any desirable manner. The feed oil is introduced into initial contacting unit I by means of feed line 3. The feed oil flows upwardly through unit l and contacts a bed of zeolite which preferably comprises a small particle size so that a large surface area is secured. Temperature and pressure conditions are adjusted in a manner to substantially completely remove the phenols and naphthenic acids from the feed oil. The feed oil is withdrawn from initial contacting unit i by means of line withdrawn from the system and handled in any manner desirable. At the end of 'a in which the eiectiveness of the zeolite is decreased to a predetermined elciency, the feed oil is passed into secondary zeolite contacting unit '2 by means of line 5 and withdrawn by means of line It. The zeolite in contacting unit l containing the adsorbed phenols and naphthenic acids is handled in a manner to remove and segregate these compounds and to regenerate the zeolte. This is preferably accomplished by washing the zeolite with suitable solvents. For the purposes of description it is assumed that the zeolite is initially contacted with a relatively distillate solvent having a preferential solubility for. the petroleum oil remaining in the zeolite bed. This petroleum oil washing solvent may be introduced by means of line 6 and withdrawn by means of line 1. The zeolite bed is then contacted with a solvent having a preferential selectivity for the phenolic type compounds which for the purposes of description are taken to be water. The water is xed time period introduced in'to -initial contacting plant I by meansof line 9 and withdrawn by means of line 8. Suiiicient water is introduced at a temperature and pressure which is adapted to substantially fully remove the phenols from the spent zeolite bed. The zeolite bed, free of petroleum oil and adsorbed petroleum phenols, is contacted with a solvent having a preferential selectivity for the naphthenic acid compounds.

For the purposes of illustration, this solvent is taken to be a sulfuric acid solution which is introduced by means of line II and withdrawn by means of line I0. The zeolite bed is treated in a manner to fully regenerate the same. This is preferably 4accomplished by Washing the bed with an additional acid solution which is introduced by means of line I2 and withdrawn by means of line I3, and then contacting the bed with an alkali metal hydroxide solution such as a sodium hydroxide solution, which is introduced by means of line I4 and withdrawn by means of line I5. At the end of the cycle in which the efciency of the zeolite in contacting unit 2 drops to a certain predetermined point, the feed oil is again passed into the regenerated zeolite in unit I. The zeolite-contacted oil is withdrawn from contacting unit 2 by means of line I 6, withdrawn from the system, and handled as desired. The zeolite in contacting unit 2 containing the adsorbed phenols and naphthenic acids, is handled in a manner similar to that described with respect to unit I in a manner to remove and segregate the phenols and naphthenic acids and to regenerate the zeolite. This is accomplished by initially washing the zeolite bed with a relatively low boiling petroleum solvent introduced by means of line I1 and withdrawn by means of line I8, removing the phenolic type constituents by contacting the zeolite with a preferential solvent for the phenolic type compounds which isintroduced by means of line and withdrawn by means of line I9. This solvent preferably comprises water. removed by contacting the zeolite bed with a dilute acid solution which is introduced by means of line 22 andy withdrawn by means of line 2i. The zeolite bed is regenerated by contacting the same with additional acid which is introduced by means of line 23, withdrawn by means of line 24, and with an alkali metal hydroxide solution which is introduced by means of line 25 and withdrawn by means of line 26. The aqueous solution of phenols which is removed from the respective contacting units'by means of line 40 is introduced into phenol recovery unit 21.l In this unit, when treating relatively high boiling petroleum oils the relatively high boiling phenols will separate from the aqueous layer.l The phenollayer is withdrawn from the phenol recovery unit 21 by means of line 28, while the aqueous layer is withdrawn by means of line 29 and preferably recycled as described as a phenolic solvent to the system. As the petroleum oll conf tacted is a relatively wide boiling fraction and contains relatively low boiling and relatively high boiling petroleum phenols, it may be desirable to fully recover the relatively low boiling phenols from the aqueous layer by distilling the same prior to returning the aqueois layer as solventto the zeolite contacting units. This is accomplished The naphthenic compounds are by passing the aqueous layer to still 30, distilling thesame under operating conditions adapted to remove overhead the aqueous layer by means of line 3I,r`and to remove as the bottoms the relapowdered zeolite and constituents, removed from the respective con-V tacting plants by means of lines I0 and 2|, respectively, is similarly handled in a manner to segregate the naphthenic acids. The acid solvent is introduced into naphthenicacid recovery plant 33 in which a layer separation will occur between the acid solution and the naphthenic acids. The naphthenic acids are removed by means of line 34 and further refined as desired, while the acid layer is withdrawn by means of line 35 and preferably recycled as acid solvent to the contacting plants as described.

Referring specifically to Figure 2, feed oil is introduced into the system by means of line 50. The feed oil is mixed with a quantity of "zeolite which for purposes of illustration is taken'to be which is introduced from zeolite bin 5I by means of screw conveyor 52.

.- The oil and the zeolite are passed through mixer 53 and passed as a slurry by means of line 54 into agitating plant 55 which may compriseany suitable number of agitating units arranged in Complete mixing is se-y any`desirable manner. cured by means of agitator 56. 'I'he mixture is withdrawn from plant ration of the solid phase from the'liquid phase may be facilitated by any desirable means such as baffles, settling means, and the like. The treated oil is withdrawn from unit 58 by means of line 59 and handled in any desirable manner. TheY zeolite containing adsorbed thereon the phenolic type compounds and naphthenic acids' recovery unit 64 by means of line 65, the phenols are removed by contacting the zeolite with a solvent having a preferential solubility vfor zeolite is passed 68 by means of of description is assumed to be a dilute acid solution which is introduced by means of line 'I0 and withdrawn by means of line 1|. The zeolite, free of adsorbed phenolic type compounds and naphthenic acid type constituents, is handled in a tion which is introduced by means of line 18 andv 19. The zeolite is withdrawn by means of line 55 by means of linel 51 and introduced into settling umt 58. The sepathe aqueous solution to unit et..

withdrawn from the latter stese by means oi line .8l and recycled to the system as described. The

distilled or further renned in any er desirable. Under certain conditions when the petroleum oiltreated is of a relatively wide boiling range and the aqueous soluon cons relatively low boiling soluble phenols, it may be desirable to distill the aqueous solution withdrawn from recovery unit di in order to remove the relatively low boiling phenols prior to recyclina The acid solu-n tion containing the naphthenlo acids Withdrawn from unit dd by means ol line'll is passed to naphthenic acid recovery unit et in which a layer separation occursbet'tveen the naphthenic acids and the dilute acid solution. The naphthenic acids are withdrawn from the system by means oi line te, distilled or further renned in any manner desirable. The dilute acid solution is withdrawn from unit te by means of line teV and recycled to unit td.

The processes oi the present invention may be Widely varied. Although the method may be employed for the recovery and segregation of phenolic type constituents and naphthenic acids from any feed oil, it is particularly applicable in the recovery of relatively high boiling petroleum phenols and petroleum naphthenic acids per hour. The preferred rates are iromtwo to four volumes or oil per'volume oi zeolite per hour. When employing a slurry. the amount o! slurry is preferably in the range from one volume ufl zeolite per fifteenl to twenty-ilve volumes of o Although it is not essential, it is preferr that the zeolite after contact with the oil be washed with a solvent which will remove occludw oil portions from the zeollte prior to treating the zeolite to remove the adsorbed phenols and naphthenic acids. This solvent may be any relatively low boiling hydrocarbon. A desirable material comprises naplithal boiling in the range fromabout 300 F. to 420 F.

The phenols are preferably removed from the zeolite by treating with water at normal temperatures and pressures. The amount oi water Aemployed may vary widely depending upon the quantity of phenols present and the particular zeolite employed. vIn general it is preferred 'to employ from about one to four volumes of water per volume of 'zeolite in orderv to displace the phenolic type constituents. A preferred modlcatlon of utilizing water at normal temperatures and pressures for the displacement of the L phenolic type constituents is to agitato the mass with air or a similar agitating means. Under from petroleum oils boiling in the pas oil and lubricating oil boiling range. These substances, due to their characteristics, have heretofore been relatively dimcult to segregate.

The adsorbent employed is selected from the class of alkali metal alum silicates of the zeolite type, but preferred materials are naturally occurring hydrated allrali metal aluminum silicates, particularly a naturally occurring hydrated sodium aluminum silicate. Although a relatively large particle size may be employed, in general it is preferred to employ zeolite of relatively small particle size, particularly powdered zeolite.

The operating conditions lilrewise :may be widely modiiied. The flow of the respective treating agents may be either upow or downdow. Temperatures and pressures may vary and `will depend upon the particular feed 'oil being treated, the quantity, and character oi the phenols and naphthenic acids present, as W as upon the particular aeolite being used and upon the feed rates and particle size. in general it is preferred to employ atmospheric tempera-u tures and pressures, although temperatures in the range from about 30 l. to 250 l. may be employed in particular instances. if the petrof leum oil be of a relatively high viscosity, it may be desirable to employ heating means or to dilute the oil with an inert dilution solvent, as for err-g ample a relatively low boiling petroleum oil or with a relatively low boiling hydrocarbon con= stituent. The feed rates may vary considerably depending upon the general. operating conditions, the character oi the feed oil being treated, as `vvell as upon the type of zeolite being employed. When the process comprises the ution of stages, feed rates are in the general range from one to seven volumes or oil per vole ol neolite certain conditions it may be desirable to employ heated water or steam in order to remove the phenols, although in general this method is not preferred. The, aqueous solution, after removal from the zeolite bed, will form two phases com-` prising a phenol phase and an aqueous Water phase. The phenol phase' is separated and may be further rened in any manner desirable. llthough the aqueous phase may be distilled in order to remove any relatively low boiling soluble phenolic type compounds present, it is preferred to recirculate the same as a phenol solvent directly to the zeolite contactingV units.

The acid solution employed for the removal of the naphthenic type constituents from the zeolite likewise may vary considerably. Any mineral acid may be employed, although in general it is preferred to utilize a dilute sulfuric acid having an acid concentration ln the range from about 2% to 10%. A particularly desirable solvent for removing naphthenic type constituents from the zeolite comprises a 5% sulfuric acid solution. This solution, after the removal of the naph@ thenic acid constituents, is likewise preferably recycled to the system as described.

The spent wollte, free of naphthenic acid and phenolic type constituents, y be died in any suitable :fiz-y in order to reerate same. .Although the spent zeolite, iree of the phenols and naphthenic acid constituents, may be satisfactorily additional water, or by Washing -with a ethyl alcohol solution or equivalent, it is pre=l 'ierred that the spent zeolite be regenerated by regenerated by washing with.

Example 1 A petroleum distillate boiling in the kerosene i boiling range, having a phenol number1 of 200, was contacted with a zeolite of the following composition at atmospheric, temperatures and pressures:

Weight, per cent 1.51

N820 5 69 ilas 45.67 F8203 l 27.11 cao 2.00 MgO 4.74 Carbon as carbonate 1.18 Per cent ignition loss 8.50

lA 200 phenol number is equivalent to 0.2% of phenols, expressed as equivalent m llograms of tertiary amyl phenol per 100 millilitres of oi The results of the operations were as follows:

Phenol number Feed stock 200 Zeolite contacted stock (fresh zeolite) 0 Zeolite contacted stock (partially spent zeolite) 20 By oontaoting the zeo1ite initially with about two volumes of water per volume of zeolite at atmospheric. temperatures and pressures and simultaneously blowing with air, substantially the entire quantity of phenols were displaced and separated as an oily layer with the water. The naphthenic acids were displaced and separated by contacting th zeolite with a 5% sulfuric acid solution.

The spent zeolite was regenerated in a number of operations as follows:

Example 2 A Talang Akar kerosene was treated in a man- Direct oxid Color tion color Original Talang A'kar kerosene... H3 Saybolt. 3M Robinson. (l) After passage through zeolite.. +20 Saybolt.. +17 Saybolt.

Apparently the solid reagent of the present invention reacts with the naturally occurring acidic oxygen containing compounds to form reactionproducts which may be readily regenerated from the reagent. The regeneration operation may be controlled in a 4manner to preferentially rst, regenerate they phenolic type y constituents which may be separated. After separation of the phenolic type constituents the naphthenio acid constituents may separated.

What we claim as new and wish Letters Patent is as follows:

1. Process for the recovery of naturally occurring phenols from mineral oils which comprises contacting feed oils containing these compounds With a solid zeolite under conditions to remove these compounds from the oil, separating the oil and the solid reagent and recovering the naturally occurring phenol compounds from the solid reagent.

2. A process in accordance with claim 1 in which said oil is a petroleum oil boiling in the kerosene boiling range and in which said solid reagent is a naturally occurring hydrated sodium aluminum silicate.

3. Process as dened by claim I` in which the naturally occurring phenols are recovered from the solid reagent by initially treating the reagent with water and then treating the reagent with a dilute acid solution.

MINOR C. K. JONES. f BARNEY R. STRICKLAND.

to protect by be readily regenerated and-v 

